Iron, does ultra high exist?

[vinnland]

So, Ive been playing this game for a while now. Every time I found iron, it was through cave exploring. One time I found two massive veins right next to each other.

When I checked the prospecting reading for the veins I did fine, they were all "poor" or "very poor".

Now, in my current game, I haven't found iron in caves, but I also have prospected lot's of the map and haven't seem iron higher than poor.

Does more than poor exist or is it like the other smaller ores (like borax) that stay small?

[Never Jhonsen]

I too haven't seen anything more than poor on Hematite. I couldn't 100% say "It doesn't show bigger than poor", as there isn't a list of common sizes for various ores (that I know of), but based off my experiences, finding a Poor reading of Hematite is more that good enough to start digging

[Shoom]

High readings do exist, needless to say they're quite rare. I think I've come across 2 or 3 in total.

[Zane Mordien]

You must just have a bad location. I prefer to find at least "decent" if possible. That being said, poor is good enough if you are persistent. I often mine for iron if poor is the best reading near my base. It usually takes about 4-5 vertical shafts to find it.

[Cattastrafy]

Iron and some of the other rare metals are actually quite easy to find with a very poor or poor reading. I think limonite and hematite or a bit more reliable than mag though.

I get excited when I find very poor reading for iron and I'm looking for it. Just find the "best" spot (even if still very poor) and dig a straight shaft down through the eligible rock stratas till you hit the point it can't spawn (look on the mining wiki for deets). Do a prospect every 10 or so blocks as soon as you're in the eligibility zone. 

Never have had a very poor reading that didn't have a node down there, usually find it in the first three shafts or so.

[LadyWYT]

Oh they definitely exist. I've found Ultra High readings of both hematite and magnetite several many times. When it comes to finding what's actually there though, it's a lot easier to find hematite than magnetite. Pretty much all high readings of hematite that I've checked had hematite available, but I've checked several ultra high readings of magnetite and found nothing.

In any case, it's worth checking Poor readings if you've got nothing better to work with, especially for iron. To my knowledge, the reading only indicates the chance of the ore spawning, not so much the deposit size. Since iron deposits are so large, there will be plenty of ore to dig up if it did spawn, even for a smaller node.